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Keeping the wings level in a stall

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Keeping the wings level in a stall

Old 10th Aug 2010, 02:35
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Keeping the wings level in a stall

I would like to receive experiences and opinions on the techniques taught and used for keeping the wings level during deliberate approach to a stall.

It has become apparent to me that the technique I have been taught, and practiced in many types over many years, is not universal. I am required from time to time to stall different aircraft as a part of evaluation of their flight characteristics. When flying alone, I employ the technique I have been taught (it's kinda instinct now), and which has been reinforced to me by those who oversee what I do. However, on occasion, I am conducting stalls in the company of other pilots, and even with preflight briefing, find that some of those pilots use techniques which differ considerably from mine.

Though the wisdom of the experienced pilots is valuable, the new pilots here are equally important, as they have just received the training, and perhaps do not yet have "habits" overlying that training yet!

Tell me how you keep the wings level, and why you do it that way...

Thanks, Jim
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Old 10th Aug 2010, 05:34
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I keep the ball in the middle with rudder input and gently release rudder pressure as I reapply power
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Old 10th Aug 2010, 06:21
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Use rudder to keep wings level/ball centered, never use aileron near or at the stall (unless you want to spin )
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Old 10th Aug 2010, 06:26
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As said, gentle movements with rudder to keep the ball centered (this is actually the most important thing), ailerons in neutral (try not doing so in proper stall training aircraft, e.g. Tomahawk and you'll see why), the elevator is in a position for required angle of attack.

As for recovery, full throttle isn't optional, speed of releasing (and pusihing) the stick varies from instructor to instructor. On proper aircraft it is neccessary to push the stick forward a little in order to brake stall, but for C172-like it is enough to just release stick and the nose drops. In my opinion, nose should be lowered (and thus reduced AoA) as quick as possible, disregarding of passengers feelings (as one of my instructors said, stall recovery should be slow and smooth), since stall isn't really state of aircraft I'd like to be in with aircraft full of passengers.
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Old 10th Aug 2010, 07:30
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The technique employed can be type-specific. For example, one (modern) type I fly has effective ailerons right through into the stick hard back, fully stalled state, but be wary of any rudder input. So, horses for courses.
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Old 10th Aug 2010, 08:50
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Rudder.. though mishandling that may (a/c dependent) tend to pitch one into rotation, as much as aileron missuse may on others. Also, in my experience, once fully stalled, it can be remarkably difficult to enter the spin, even when you're trying!

As for breaking the stall, I'm firmly of the stick and more stick principle. Primacy perhaps as I learned on gliders, but the 'minimum height loss' - pitch level and apply power technique really irks me. Fly the wing; it can be stalled or unstalled at any attitude. That said, there is no need to be violent, just positive.
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Old 10th Aug 2010, 09:52
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My 2ps worth...

Keeping the wings level in a stall
Why do you want to? Is that really important / a priority?

2 priorities are:
1. Unstall the wings - only now do you have "control" of the aircraft.
2. Minimum Ht loss in the whole stall / unstall / climb cycle.

1 is achieved by reducing the AoA. Not "pushing" the stick, but relaxing back pressure / easing it (centrally) forward until the wing is unstalled and no more. The moment the wing is unstalled, you have ailerons to level the wings.

2 is achieved by:
a. Only lowering the AoA until the wing is unstalled, and not "shoving" the stick forward.
b. Power
c. A prompt ease out of "dive" and into a climbing attitude (without further stalling the aircraft).

Clearly some teaching / types concentrate on the rudder - fine, if that is on good authority (in authorised manuals) - but I cannot recall seeing it on types I fly.

The aim is a simple repeatable drill that is being practiced for a stressful / hazardous situation. Rudder in the stall might work for a TP, but can also provoke a spin if used incorrectly, so IMHO not a good tactic. A prompt reduction in AoA as priority #1 will minimise any wing drop...

As a (Q)FI on various types (SEP, Jet) the usual technique errors I observe / debrief / re-practice on are excessive stick forward / nose down attitude, and then far from optimal transition back to a climb e.g. lose more height / eventually climbing 10K+ above what could be achieved.

NoD
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Old 10th Aug 2010, 10:52
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Why would you want to? Simple, to execute a falling leaf, in a Tiger anyway. Great fun and a great challenge.
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Old 10th Aug 2010, 11:28
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Perfect, more contributions please. Keeping the wings level to the greatset extent possible through the stall is the objective....
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Old 10th Aug 2010, 11:31
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I was always taught to keep the aircraft balanced but DON'T try to pick up a wing in the stall using rudder. Simply unstall and then worry about wings level.
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Old 10th Aug 2010, 12:34
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It depends upon what you are trying to achieve. Firstly, you initially talk about the 'deliberate approach' to the stall so, in the early stages (for argument's sake pre-stall warner), I would continue with the ailerons. At the later stages, the key bit is to keep the controls centralised and remain balanced (ball). As this is an exercise, if you have an unintentional roll at this point onwards, I would recover pre-stall. Conversely, if you are attempting to generate/demonstrate a wing drop then continue as suggested above.

In you last post you talk about the objective being to keep he wings level throughout the stall. Can I presume this means you stall the aircraft and are not seeking immediate recovery? Instinct tells me that, in general terms, pilots shouldn't be fiddling with any of the aircraft controls (aileron/rudder) during a stall unless they are trying to achieve something other than recovery. Under such circumstances, the actions are very dependent upon aircraft type.
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Old 10th Aug 2010, 12:54
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In the PA38 Terrorhawk I was taught to use the rudder to keep the wings level; apparently the ailerons were ineffective during a proper stall and could cause a spin...

Otherwise, I use the ailerons to keep the wings level, and use the rudder to keep the ball in the middle because yaw during a stall is potentially bad news.

Certainly on the TB20 this is fine; it does everything it says on the tin, with no suprises, ever.

Recovery is a smooth re-application of power, back to the cruise setting, together with moving the yoke forward, so one recovers to cruise speed without any real loss of altitude (under 100ft). In the FAA IR they get you to do this partial panel

Obviously an emergency recovery would use a bit more power than that but if you quickly whack the throttle fully forward you suddenly have a lot of yaw to deal with; don't try this in a TBM, evidently...
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Old 10th Aug 2010, 13:12
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Otherwise, I use the ailerons to keep the wings level, and use the rudder to keep the ball in the middle because yaw during a stall is potentially bad news
This is also fine in my Rallye where I can use the ailerons even when completely stalled and falling with style. However the input of aileron on some types can increase the stall to one wing (the down aileron side) due to the increased AoA on that wing and so likely if you tried to pick up a wing this way in some aeroplanes the aircraft would just roll more towards the wing-down side and you may well depart into a spin. I know you know this but I'm pointing it out for the benefit of the audience
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Old 10th Aug 2010, 14:01
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I remember being checked out in the C-172 after getting my license in the C-150.

The instructor stalled it; then with the stick all the way back, flopped the ailerons back and forth from stop to stop -- wings stayed level.

The glider checkout instructors seem to get a bit miffed when I use rudder to stay coordinated approaching the stall
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Old 10th Aug 2010, 17:26
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The rudder should be used to STOP the yaw this should prevent wing drop.

Rudder must NOT be used to "pick up" a wing only to prevent further wing drop.

Stall + Yaw= Spin!
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Old 10th Aug 2010, 17:33
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The only way to create a rolling moment with the rudder is to induce a sideslip. Rhetorical question: Would we rather stall in coordinated or uncoordinated flight?

The scenario: Reduce the airspeed, add back pressure, ailerons neutral, apply rudder pressure. I just described entry into a spin. To me it sounds a bit peculiar to have this scenario described as the proper way to prevent a spin.

What I was taught, and use, is to apply slight, smooth aileron inputs to keep wings level, using rudder for coordination. At the stall, ailerons neutral and use rudder to counter any yawing tendencies. If a wing drops at the stall, e.g. if one uses too much aileron or flies a plane that does have a tendency to stall over a wing, then that is just the way it is; it will be a stall with a wing drop. Recovery from a stall with a wing drop is something we all learned during training, right...?

Even if one uses too much aileron and provokes a wing drop, a spin should not result provided one uses rudder to counter adverse yaw and maintain yaw control.

Apart from my training, both standard references I use for basic flight procedures and techniques (the FAA's Airplane Flying Handbook and John S. Denker's See How It Flies) suggest coordinated use of aileron and rudder to maintain wings level during the approach to stall.

Nevertheless, intrigued by what I have been reading here in the last few years, I decided to go up and try the "keep wings level using rudder with ailerons neutral" approach to see for myself. I used a C172. After some rather spectacular departures for a C172 I decided it was just as bad an idea as I thought before I tried it.

The problem with that method, IMV, is what happens if it fails. If you manage to keep the wings level with small inputs, i.e., do not have to try and catch a wing that shows a tendency to drop with either rudder or aileron, both methods work. But if you fail, the coordinated aileron method results in a rather benign wing drop, whereas the rudder only method results in an incipient spin.
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Old 10th Aug 2010, 18:08
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I would suggest you should approach this question from a different direction.
Assuming we are not talking about aerobatic training, I think it is imperative that one does not think about the stall entry as a stand alone exercise. There is no reason the aircraft should stall at altitude. If the aircraft has stalled than the guy/gal at the controls has seriously screwed up and if close to the ground this is a full blooded emeregency. Therefore it is vital that the instinctive reaction of the pilot to a stall is to lower the nose to unstall the wing and to simulataneously use all necessary rudder to stop the aircraft from yawing thus making it impossible for it to enter a spin. In training the worse the stall entry the better as if the student can reliably recover from a banked yawed entry than they will be well prepared if they ever get cought for real. Finally the best recovery from a stall is to not stall in the first place therefore training to recognize the condition which indicate a potential stall is possible is just, if not more, important than stall recovery training. Stall entry training is simply a necessary precursor to learn the real lesson, stall avoidance and recovery, and should never IMO be presented as an exercise in itself.
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Old 10th Aug 2010, 19:16
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Why has no one specified what type of stall they are doing, power on, off, accelerated?
In most single trainers, doing a power on departure stall, you will most certainly drop a wing at the break of the stall if you kept the ball centered and the wings level during entry, does anybody know why.
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Old 10th Aug 2010, 19:35
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...the best recovery from a stall is to not stall in the first place...
Applying that principle to engine failures would have eliminated one of the longest current threads on PPRuNe!
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Old 10th Aug 2010, 19:38
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barrow, consider the relative airflow generated by the propeller in a power-on stall.
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